Dual-Band UHF Folded Dipole RFID Tag Antenna Loaded With Spiral Resonator

In this paper, a dual-band UHF RFID tag antenna operating at 867 MHz and 956 MHz has been proposed. Perturbation method is used to obtain dual-band response by loading a 2-turn spiral resonator (2-SR) to a single band folded dipole antenna (FDA) operating at 912 MHz. The 2-SR perturbs the electrical length of the FDA and splits the resonant frequency at 912 MHz into the two resonant frequencies of interest. Reflection coefficients of -13.25 dB and -13.34 dB have been recorded with corresponding read ranges of 5 m and 3.3 m in 866–869 MHz band and 950–956 MHz band respectively.